CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY ( UNAUDITED ) (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Other comprehensive income (loss), net of tax:
Dividends: declared and paid (in dollars per share)	$ 0.20	$ 0.15
Convert Voting Shares to Class A Common Shares (in shares)		2
Repurchase Class A Common shares (in shares)	3,106,925	2,394,944
Exercise of employee stock options: shares issued (in shares)	589,331	299,001
Other stock-based compensation, net: shares issued (in shares)	301,544	247,289
Other stock-based compensation, net: shares repurchased (in shares)	106,677	83,675